This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In the past year, we focused on understanding the molecular basis for the species differences in V1aR expression. We have been working to explore the role of polymorphisms in the vole V1aR gene in regulating gene expression and social behavior by attempting to create 3 knock-in mouse lines with different promoter elements. We now have ES stem cells which will be used to create the mouse lines. We have completed a comparative evolution study of the V1aR promoter and microsatellite polymorphisms in great apes and several monkey species which was published in BMC Evolutionary Biology. We have begun a selective breeding program to create a line of prairie voles that differ in terms of their affiliative behavior and are now in our 3rd generation. Finally, we have developed the technology to create germ-line transgenic voles. These studies have important implications for understanding the mechanisms underlying social cognition disruptions in psychiatric disorders such as autism.